Signal MCP vs Cv MCP Server — MCP Server Comparison | AllMCPs
Side-by-Side Model Context Protocol Comparison
Signal MCP vs Cv MCP Server
In-depth architectural comparison of the Signal MCP and Cv MCP Server MCP servers. Compare execution transports, security boundaries, tool capabilities, quality scores, and ready-to-paste client installation snippets for Claude, Cursor, Windsurf, and VS Code.
At a Glance & Executive Verdict
Signal MCP
Communication · Local stdio
Quality: 59/100 (Good) | Auth: other
Cv MCP Server
Communication · Local stdio
Quality: 61/100 (Good) | Auth: other
Verdict Summary: Choose Signal MCP if you need specialized Communication tools running via a local process. Choose Cv MCP Server if your workspace requires Communication integration with local subprocess execution. Both servers can be configured concurrently in your client's mcpServers manifest.
Which MCP Server Should You Choose?
Choose Signal MCP when:
You need dedicated capabilities in the Communication domain.
You prefer local stdio subprocess transport architecture.
Your security boundary fits: other (Free / Open Source).
Send a text message to a Signal contact. The message is delivered end-to-end encrypted. Returns the sent timestamp, which can be used as target_timestamp for react_to_message or edit_message. To reply/quote a specific message, provide quote_author and quote_timestamp (get timestamps from get_conversation). Use send_group_message for group chats, send_attachment for files/images.
send_group_message
Send a text message to a Signal group. The message is delivered end-to-end encrypted to all group members. Returns the sent timestamp, which can be used as target_timestamp for react_to_message or edit_message. To @mention a member, include their name in the message text and pass a mentions list where each entry has start (character index of the mention in the text), length (character count), and author (E.164 phone number). To reply/quote a message, provide quote_author (sender's phone number) and quote_timestamp (from get_conversation). Use list_groups to get group_id values. Use send_group_attachment to send files or images to a group. Do NOT use for direct messages to a contact — use send_message instead.
send_note_to_self
Send a note to yourself via Signal's 'Note to Self' / saved messages feature. The note is synced across all your linked Signal devices. Useful for saving reminders, bookmarks, or drafts that sync to your phone. message supports lightweight markdown for Signal's native rich text: **bold**, ~~strikethrough~~, `monospace` — use it to visually distinguish different kinds of notes (e.g. a bold title per note) instead of plain text blobs. Pass attachments (e.g. a QR code image) and quote_author/quote_timestamp (to thread a follow-up under a previous note, from a prior send_note_to_self result) to combine content in one message instead of separate calls.
Ready-to-Paste Client Configurations
Paste either (or both) of these JSON server blocks into your client config file (e.g. claude_desktop_config.json or ~/.cursor/mcp.json).
Signal MCP is categorized under Communication and uses a local stdio subprocess. In contrast, Cv MCP Server belongs to Communication using local stdio subprocess. Select Signal MCP when you need capabilities focused on communication and Cv MCP Server when you require tools for communication.
Edit the text of a previously sent message. Sends the edit via signal-cli to all original recipients; they see the updated text inline with an '(edited)' label. Only the message text can be modified — attachments, quoted replies, and reactions are immutable. The edit must reference the exact timestamp of the original message as returned by send_message or get_conversation. Edits can only be made to messages you sent; editing someone else's message returns an error. There is no enforced time limit, but Signal clients may ignore edits on very old messages. Provide recipient for a DM edit or group_id for a group edit; exactly one is required. Use when correcting a typo or updating information in a message you already sent. Do NOT use to change who a message was sent to — send a new message instead.
receive_messages
Manually poll signal-cli for new messages and store them. Prefer get_unread — it does this automatically and returns results in one call. Use receive_messages only if you want to poll without reading results.
receive_direct
Receive messages by calling signal-cli directly, bypassing the daemon. Use this as a fallback when the daemon is stuck or unresponsive — it stops the daemon, calls signal-cli receive directly, then lets the daemon restart. Prefer receive_messages (daemon mode) for normal use; use this only for troubleshooting.
list_contacts
List all Signal contacts known to this account, including names and phone numbers. Use the optional search parameter to filter by name or number substring. Returns contacts from signal-cli's local contact store. Use get_profile to fetch the current Signal profile for a specific contact.
list_groups
List all Signal groups this account belongs to, including group name, ID, members, and admin list. The group_id returned here is required for send_group_message, send_group_attachment, and update_group. Use update_group to modify a group, or leave_group to exit.
get_conversation
Get recent message history with a contact or group from local store. Automatically marks returned messages as read in the local store (does NOT send a Signal read receipt — call send_read_receipt for that).
search_messages
Full-text search across all locally stored messages by keyword or phrase. Searches message bodies using SQLite FTS — results are ranked by relevance. Only messages in the local store are searchable; messages never received on this device are excluded. Use sender to narrow results to a specific conversation. Use limit and offset to paginate through large result sets. Use when looking for a specific message or topic across all Signal conversations. Do NOT use to browse a conversation chronologically — use get_conversation for that.
send_attachment
Send one or more files or images to a Signal contact. Supports photos, videos, documents, and audio files. Use path for a single file or paths to send multiple files in one message. Set view_once=true to send media that auto-deletes after the recipient views it once. For groups use send_group_attachment instead.
send_group_attachment
Send one or more files (photos, videos, documents, audio) to a Signal group in a single message. All current group members receive the attachment via the normal Signal encrypted delivery pipeline. Provide path for a single file or paths for multiple files sent together in one message. Set view_once=true so each member can only open the media once before it disappears — ideal for sensitive images; does not apply to document types. The file must exist and be readable on the local filesystem; non-existent paths return an error. Use list_groups to obtain the group_id. Use when sharing a file with a group chat. Do NOT use for direct messages — use send_attachment instead. Do NOT use when you only want to send text — use send_group_message instead.
+68 more tools listed on main page
Cv MCP Server Tools (42)
list_messages
List messages with filtering by date, conversation, folder, workspace, creator or language.
USE WHEN: The general-purpose message reader; full bodies incl. transcript and AI summary. Max date span 183 days. `user_ids` filters by SENDER — for messages exchanged WITH someone, pass `conversation_id` from `list_conversations`. Use presigned URLs as-is.
USE INSTEAD: `get_recent_messages` for a quick look at the latest few (hard-capped at 10, no paging). `search_message_ids` for filters this cannot express — notified state, mentions or labels.
FIRST: `workspace_id` comes from `get_workspaces_basic_info` (field `id`) — call it first if you don't have one.
EXAMPLE: {"workspace_id":"ws-abc","start_date":"2026-09-01T00:00:00Z","size":25}
RETURNS: `{page, size, sort_direction, total, results_count, has_next_page, filters, results: [{id, transcript?, ai_summary?, audio_url?, creator_id, conversation_id?, duration_ms, reply_count, status, type, created_at, ...}]}`. Page on `has_next_page`/`total` — do not guess.
NARROW: pass response_fields ["total","has_next_page","results.id","results.transcript","results.created_at"] unless you need more — the full payload is much larger.
get_message
Get one message by ID, optionally expanded with related records.
USE WHEN: You have a message ID. `fields` ADDS related data (`conversation`, `creator`, `labels`) — it does not narrow the response. Use `response_fields` to narrow.
USE INSTEAD: `list_messages` when you do not have an ID, or need several messages — it already returns full bodies, so fetching each one again is wasted.
FIRST: `id` comes from `list_messages` (field `results[].id`) — call it first if you don't have one.
EXAMPLE: {"id":"msg-abc","fields":"creator"}
RETURNS: `{message: {id, transcript?, ai_summary?, audio_url?, creator_id, duration_ms, status, type, attachments?, created_at, ...}}`.
get_recent_messages
Get up to 10 of the most recent messages, each with its conversation, creator and labels.
USE WHEN: A quick "what just happened" glance. Pre-joined, so no follow-up calls for creator or conversation names.
USE INSTEAD: `list_messages` whenever you need more than 10, any date range, paging, or a filter other than conversation and language — this tool supports none of those.
EXAMPLE: {"conversation_id":"conv-abc"}
RETURNS: `{results: [{message: {...}, conversation: {...}, creator: {...}, labels: [...]}]}`. No total and no paging: the cap of 10 is the whole answer.
create_conversation_message
Post a message into an existing conversation, or reply in a thread.
USE WHEN: You have a `conversation_id`. Pass `parent_id` (a message ID) to reply as a thread. Either `transcript` or `links` is required — the schema marks neither individually, so both param descriptions say so.
USE INSTEAD: `create_direct_message` to reach people who are not already in a conversation. `create_voicememo_message` for a standalone memo.
FIRST: `id` comes from `list_conversations` (field `results[].id`) — call it first if you don't have one.
EXAMPLE: {"id":"conv-abc","transcript":"Agreed, shipping Friday."}
RETURNS: `{message: {id, link, transcript?, status, type, conversation_id, created_at, ...}}`.
ERROR BAD_REQUEST: Neither `transcript` nor `links` was provided. — Pass at least one of them.
create_direct_message
Send a direct message to one or more people, by user ID or email.
USE WHEN: Reaching people outside an existing conversation. Address it with `to.user_ids` or `to.emails`. Requires `transcript` or `links`.
USE INSTEAD: `create_conversation_message` when a conversation already exists — a DM starts a separate thread rather than joining it.
FIRST: `to.user_ids` comes from `search_users` (field `id`) — call it first if you don't have one.
EXAMPLE: {"to":{"user_ids":["user-abc"]},"transcript":"Quick question about the deck."}
RETURNS: `{message: {id, link, transcript?, status, conversation_id, created_at, ...}}`.
ERROR BAD_REQUEST: A user ID is invalid, or neither `transcript` nor `links` was provided. — Resolve people with `search_users` — never pass a display name as a user ID — and include a transcript or links.
create_voicememo_message
Create a voice memo, either from text (spoken via text-to-speech) or from an audio file at a URL.
USE WHEN: Pass `transcript` (2-5000 chars) to have Carbon Voice speak the text, or an https `audio_url` to upload audio, which wins over `transcript`. File it with `folder_id`, whose type must match, or a `workspace_id`.
USE INSTEAD: `create_conversation_message` to post into an existing conversation, or `create_direct_message` to send to specific people. A voice memo is standalone and lives in a folder or workspace.
EXAMPLE: {"transcript":"Reminder to review the pricing deck before Friday."}
RETURNS: `{message: {id, link, transcript?, audio_url?, duration_ms, status, type, created_at, ...}}`. `status` is often `processing` at first.
ERROR INVALID_AUDIO_URL: `audio_url` is not https, unreachable, too large, timed out, embeds credentials, or resolves to a private address. — The message gives the reason. Use a public https URL, or pass `transcript` instead.
ERROR BAD_REQUEST: None of `transcript`, `audio_url` or `links` was provided, or the transcript is outside 2-5000 characters. — Provide one of the three, and keep the transcript within the length limits.
add_attachments_to_message
Attach one or more link URLs to an existing message.
USE WHEN: Adding external links to a message that already exists.
USE INSTEAD: `create_message_share_link` to share a Carbon Voice message outward — that produces a link, this consumes them.
FIRST: `id` comes from `list_messages` (field `results[].id`) — call it first if you don't have one.
EXAMPLE: {"id":"msg-abc","links":["https://example.com/spec"]}
RETURNS: `{...}` confirmation with the resulting attachments.
get_user
Get a user's full profile by ID — names, languages, voice settings, workspace roles.
USE WHEN: You already have a user ID and need complete details.
USE INSTEAD: `search_user` / `search_users` to FIND someone by email, phone or name. `get_current_user` for the caller — this tool needs an explicit ID and will not default to you.
FIRST: `id` comes from `search_users` (field `id`) — call it first if you don't have one.
EXAMPLE: {"id":"user-abc"}
RETURNS: `{id, first_name, last_name?, languages, voice_gender, workspace_ids, workspace_roles, user_type, created_at, ...}`.
NARROW: pass response_fields ["id","first_name","last_name","workspace_ids"] unless you need more — the full payload is much larger.
search_user
Find a single user by email, phone or name.
USE WHEN: Resolving ONE person. Supply exactly one of `email`, `phone` or `name`. Name search only matches your own contacts.
USE INSTEAD: `search_users` for several people in one call — it takes arrays and saves a round trip per person. `get_user` when you already have the ID.
EXAMPLE: {"email":"someone@example.com"}
RETURNS: `{id, full_name, first_name, last_name?, link, image_url?, languages?, ...}`. Use `id` wherever another tool asks for a user ID.
ERROR NOT_FOUND: Nobody matched, or a name search hit a non-contact. — Try an email or phone instead of a name; name search is limited to your contacts.
search_users
Resolve several users at once by emails, phones, IDs or names.
USE WHEN: Turning a list of people into user IDs in one call — the right first step before any tool that takes user IDs. Name search only matches your contacts.
USE INSTEAD: `search_user` for a single lookup. `get_user` for a full profile once you have the ID.
EXAMPLE: {"names":["Brett"]}
RETURNS: Array of `{id, full_name, first_name, last_name?, link, languages?, ...}`. If a name returns more than one candidate, ask which person was meant rather than guessing.
NARROW: pass response_fields ["id","full_name"] unless you need more — the full payload is much larger.
get_current_user
Get the calling user's own identity, workspaces and settings.
USE WHEN: Establishing who you are acting as, or finding the caller’s workspace IDs before a workspace-scoped call. Takes no arguments.
USE INSTEAD: `get_user` for somebody else (it requires an explicit ID). `get_workspaces_basic_info` if you only need workspace IDs and names — it is far smaller than this response.
EXAMPLE: {}
RETURNS: `{success, user: {user_guid, first_name, last_name?, email_txt?, phone_txt?, workspace_guids, identities, entries, environments, lifecycle_events, notification_settings, settings, ...}, settings: {...}}`. This payload is LARGE — several unbounded arrays and an open settings map.
NARROW: pass response_fields ["user.user_guid","user.first_name","user.email_txt","user.workspace_guids"] unless you need more — the full payload is much larger.
list_conversations
List your conversations from the last 6 months, optionally filtered by participants, type and name.
USE WHEN: Finding a `conversation_id`. Filter with `user_ids` plus `match`, `types` and `name` — YOUR DM with someone is `user_ids: ["<their id>"], types: ["directMessage"]`. You are always an implicit participant, so never pass your own ID. Filters AND together; if several match, ask which was meant.
USE INSTEAD: `get_conversation` when you already have an ID and want full detail — this returns only id, name, workspace_id and type.
EXAMPLE: {"user_ids":["user-abc"],"types":["directMessage"]}
RETURNS: `{results_count, results: [{id, name, workspace_id, type}]}` where type is `directMessage` | `customerConversation` | `namedConversation` | `asyncMeeting`. No paging: `results_count` is what is returned, after filtering. `name` adds `unfiltered_count`: rows the name was matched against, AFTER `user_ids`/`types`. ALWAYS check it before saying no such conversation exists. 0 of 47 means none matched that string (misspelt, or >6 months old); 0 of 0 means your other filters left nothing — not that the caller has none. Widen the filters or ask; never report it does not exist.
Full Signal messenger MCP server and CLI. Send/receive messages, manage groups and contacts, search history, handle attachments and reactions. Runs locally via signal-cli — no third-party servers.
MCP Server that connects AI Agents to Carbon Voice. Create, manage, and interact with voice messages, conversations, direct messages, folders, voice memos, AI actions and more in Carbon Voice.